juju/juju — pull request #195 by davecheney (2014-06-30 03:49:23+00:00)
Title: version: fix package and tests

Introduce `mustOsVersion`, which replaces `osVersion`, and panics if the version cannot be determined.

`osVersion` now returns an error value if it cannot determine the series.

Fix the tests so they actually _compile_ and _pass_ on OSX.